[ferrarispider]

Like many 355s my speedo has a mind of its own and has for the last two years, sometimes it works sometimes it only goes to 80ish mph then goes backwards. I have tried to fix the problem and even asked my local shop to look at it while being serviced but it is always working when it goes in.
Any way the question i want to ask is, last night going through the gears from 3rd,4th,5th,to 6th gear i was going for it on a clear straight of empty road and my rev counter indicated 7800rpm before i had to ease of, i sometimes hit around 7500rpm and was wondering what does this rpm figure = interms of MPH? Can anyone shed light on this please.And what RPM would be the top MPH (180ish). I know it may seem a sad question but i need to know.

 

[Dj Dirk]

so, if i understand that correct, when you go above 80mph, your speedo goes slower??

now that is great

yes officer, i swear, i was only doing 30mph :green:

 

[Andrew]

I'm surprised the dealer/shop has not found the speedo to be faulty.

In response to your question at max speed (~184 mph) the car will be red-lined at about ~7500 RPMs So if you are in sixth gear and have the car red-lined, you are moving fast :green:

 

[ferrarispider]

Thanks for your responce Enzo, and no i have not red lined yet in 6th only 7800ish rpm, so i have another 800rpm to go, if its at all posable

 

[4kids3fish]

ferrarispider,

First, the owner's handbook should give the speed vs rpm in each gear. For example my 87 Mondial at 7750 does approx 70 / 100 / 140 / 200kmph in gears 1-4, and 250 in 5th at 7500, according to the book.

Secondly, I had a similar problem with the electronic speedo. It started "flicking" and then even got slower as I went above about 120kmph! The problem (along with a few other electrical gremlins) disappeared when I disconnected, properly cleaned-up & reconnected both battery terminals PLUS the earth strap to the body PLUS the battery cut-out connections. Looks like a dodgy earthing circuit can cause the electrics to be a bit flaky.